As safety concerns for rail systems become an increasingly important public issue, a need has arisen for implementing an automated control system, such as positive train control (PTC), which incorporates automated systems and processes for controlling a train. Distributed power systems allow locomotives to be distributed throughout a train by utilizing radio communication to remotely control the operation of each locomotive from a lead locomotive. Typically, distributed power systems allow the crew of a train riding in the lead locomotive to monitor and control tractive effort and braking power of multiple train consists comprising one or more locomotives and an associated group of cars. Each locomotive of the train may be operated in either a lead or a remote role thereby allowing train consists to be joined together along high traffic corridors and separated for intermodal or general freight service. In this manner, distributed power systems allow safer, more efficient hauling of all types of freight over all types of terrain. Knowledge of the order and position of locomotives in each train consist, and the exact location of the very front end of the consist at the front end of the train is required to ensure safe operation and handling of the train. However, the order and position of locomotives and cars may periodically change as train consists are joined and separated or cars are added to or removed from a particular consist. Furthermore, position location sensors such as Global Positioning System (GPS) sensors on a locomotive may malfunction or enter an area where they are not able to receive or transmit information regarding their location.
One attempt to improve the safety and efficiency of railroad operations by utilizing a global positioning system to determine relative locomotive position in a train consist is disclosed in U.S. Pat. No. 5,969,643 of Curtis that issued on Oct. 19, 1999 (the '643 patent). The '643 patent provides a system for determining the relative position of locomotives in a consist, wherein the locomotive position information may be utilized to track and verify the configuration of the consist. The system includes a receiver mounted to a remote locomotive within a train consist, with the receiver receiving a reference signal from a global positioning system (GPS) from which a position of the remote locomotive is determined. A processor is operatively coupled to the receiver, and the processor determines a relative position of the remote locomotive in the train consist based on the received signal.
While the system described in the '643 patent may help with tracking and verifying the location of locomotives within a train consist, it may be less than optimal. In particular, the system of the '643 patent does not address situations where particular receivers on certain locomotives are no longer functional for various reasons including malfunctioning electronics and the locomotive being in a tunnel or otherwise obstructed from receiving or sending signals. Additionally, the system of the '643 patent only contemplates determining the position of functioning receivers on the leading and trailing locomotives, and does not provide for determining the location of the very front of a consist or the front of a train.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems in the art.